[time-nuts] homebrew H maser
jfor at quik.com
Thu Sep 2 16:59:25 UTC 2010
> jimlux at earthlink.net said:
>> The gas diffusing out through the drilled bolt.. sure it's drilled, but
>> conductance is so patheticaly low, you're literally waiting until the
>> molecules happen to randomly bounce their wey up the hole.
> I've never worked with vacuum gear.
> I assume "drilled bolt" refers to a bolt through a drilled hole so there
> some slop between the bolt and the hole.
No. It's used where a bolt goes into a blind hole. It is to vent the
trapped gas more quickly to reduce "virtual leaks"
> Can I use vacuum grease as a seal around the bolt? Or does it outgas too
> much if you are going for seriously low pressures?
Basically no. SS bolts are lubed to prevent sieze up, but not in vacuum.
> Can I use a soft(er) metal washer and mash it to a gas tight fit by
> tightening the bolt enough?
Conflat (and other) fittings use OHFC copper gaskets (one use only. Take
it appart and you must use new ones). Also Indium and Gold are used.
> How low a pressure does a H maser need? Where is it relative to say
> fingerprints outgassing?
The vacuum areas must be really clean. Think vapor degreasing with Trichlor.
> Is there an easy to understand scale of difficulty? (like dishes rattle
> for the Richter scale)
On a scale of 1 to 10:
1 getting a GPS DO working.
3 getting a Rb working from scratch.
9 getting a H2 MASER working scratch.
15+ getting an Ion trap working.
And, like the Richter, this is a log scale.
> These are my opinions, not necessarily my employer's. I hate spam.
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